The longer and cooler nights of autumn will soon finish the season for zinnias. (Most, but not all of the common zinnias are of the species Zinnia elegans.) They are really at their best while the weather is warm through summer and the beginning of autumn. As the garden warms up at the end of next spring, new seedlings can be planted, or zinnia seed can be sown. They like rich soil and regular watering, but are susceptible to mildew in humid spots. Sunny areas with good air circulation are best.

Like related chrysanthemums, zinnias are quite variable. Although the simpler forms remain more popular; double, cactus flowered and crested forms are also available.  Flowers can be less than an inch wide to more than five inches wide. Their color range includes white, yellow, orange, salmon, pink, red, rose, purple, lavender and even green. The narrowly oval leaves can get to about four inches long. Compact types stay about a foot tall and wide. Large types get twice as wide and more than three times as tall.